Blot the food coloring with a wet sponge; immediately press a dry absorbent cloth over the wet spot. Repeat until most or all of the dye has been absorbed into the cloth. This may be all that's necessary if the food coloring stain is extremely fresh.
Mix 1/8 cup oxygen bleach powder with 2 cups of hot tap water in a bowl. Stir with a spoon until the powder is dissolved. Dip a clean sponge into the oxygen bleach solution and blot any remaining stain, alternately soaking up the solution with a dry absorbent cloth until you've removed as much of the dye as possible.
Blot the spot with a cotton pad soaked with isopropyl alcohol to remove any remaining food coloring, if necessary. Press a dry absorbent cloth other the spot firmly; fold and repeat until the spot is dry.
Vacuum the spot once the area has air dried to remove any specks of oxygen bleach on the surface of the upholstery.